Ulrum in northern NL is a European landmark in the history of mobile communications which has come to light after after the declassification of the relevant documents (more than thirty years later) as explained in this presentation
Mr. Al Gross (left) with the original prototypes of his hand held radios from 1943-44 (they are now on display with many other related items at Virginia Tech.)
From the archives of Mr. Al Gross, as kindly given to DY.
OSS part of previous image
Actual deployed version
Mosquito - mostly wooden hence suitable for radio comms